Weird Drone Behavior

[otoe10]

Ok, so i just finished building my 2nd drone. All soldering, connections, etc. seem fine. I take it out for the maiden, and it takes off just fine. However, it seems a little under powered. Soon, it drops out of the sky, an a few seconds later it does the "beep beep beep" aka the sound when u plug it in but not the last 2. I thought it could have been my old batteries, but they are all at correct voltage. However, they may not be outputting enough under load. Any suggestions or comments?

 

[HighTechPauper]

What exactly is the "correct voltage" they are reading? Let it fail, and then read the voltage across the outside 2 balance connector pins while it is still plugged in, nothing really pops out about your description except low voltage or bad connection.